re-pete-a, I just wanted to say that I really like your timing method!
I like the specific nature of the GD system that rwcarter referred to, but it always seemed like too much to remember, and too complicated because my astrological knowledge is pretty slim.
However, your seasonal system makes good sense to me, so I'll have to try it!
The Wheel card is about randomness to me, so that would be an "it happens when it happens" card, for me. Alternately, I could see it as the whole wheel as the wheel of the year, and see if any particular point on it sticks out to me.
Here is my method for timing, since no one has shared anything similar in this particular thread:
I start turning over one card per day/week/month. I pick which increment of time to work with based on what seems plausible with the question.. for example, if someone asks "when will I hear back from that girl I gave my phone number to yesterday?", I'd use days, or if a young single woman asked when she would get married or have children, I'd use years.
I keep turning over cards, counting one day/week/month/year for each card, until one falls that seems to indicate an answer to the question. (for example, if someone said, when will I fall in love? and the second card that came up was the Ace of cups or the Lovers or something like that, I'd say within 2 months). I generally don't interpret the other cards that come up around it, just the one that indicates the outcome.
If I've drawn several cards, and none of them scream out the outcome to their question, then I would say the timing is not able to be pinpointed, or perhaps the outcome won't quite be the expected one. I might then interpret the cards that did come up to see if they give any clues as to why.